SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb528688a5505969e7b83a5f7e318ee3f4d817ff025b3b4a19d210a8e64b727b' 
  AND token = 'QGy5Cg818/jWDReaNhPpC5SPpF2DtD1SHJ9LX2aXSew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}